linux-kernel - Re: [PATCH] ovl: Prevent rw remount when it should be ro mount

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Date:	Thu, 1 Jan 2015 16:13:57 +0100
From:	Richard Weinberger <richard.weinberger@...il.com>
To:	Seunghun Lee <waydi1@...il.com>
Cc:	Miklos Szeredi <miklos@...redi.hu>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ovl: Prevent rw remount when it should be ro mount

On Thu, Jan 1, 2015 at 6:07 AM, Seunghun Lee <waydi1@...il.com> wrote:
> Overlayfs should be mounted read-only when upper fs is r/o or nonexistend.
> But now it can be remounted read-write and this can causes kernel panic.
> So we should prevent read-write remount when the above situation.
>
> Signed-off-by: Seunghun Lee <waydi1@...il.com>

This patch makes zero sense, did you use the wrong diff?

> ---
>  fs/overlayfs/super.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 84f3144..1faa5e5 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -522,6 +522,14 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
>         return 0;
>  }
>
> +static int squashfs_remount(struct super_block *sb, int *flags, char *data)
> +{
> +       if (!ufs->upper_mnt || (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY))
> +               *flags |= MS_RDONLY;
> +
> +       return 0;
> +}
> +
>  static const struct super_operations ovl_super_operations = {
>         .put_super      = ovl_put_super,
>         .statfs         = ovl_statfs,
> --
> 2.1.3
>
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-- 
Thanks,
//richard
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